B744, en-route, north of Anchorage AK USA, 1989

B744, en-route, north of Anchorage AK USA, 1989

Summary

On 15 December 1989, a Boeing 747-400 positioning for a planned en-route stop at Anchorage with crew awareness of a significant volcanic eruption in progress some 150 nm upwind entered volcanic ash during descent north northeast of the airport. When an attempt to climb out of the ash using full thrust was made, all engines failed. After repeated and eventually successful engine restart attempts as a 13,000 feet loss of altitude occurred, the fight was completed. The Report of the comprehensive NTSB Investigation remains unpublished with only a brief factual report containing neither Safety Recommendations nor Safety Actions issued.

Description

On 15 December 1989, a GE CF6-powered Boeing 747-400 (PH-BFC) being operated by KLM on a scheduled international passenger flight from Amsterdam to Tokyo via Anchorage as KL867 was making its initial descent into Anchorage in day VMC when it entered a volcanic ash cloud. Almost immediately, ash dust entered the cabin air and the engines began to malfunction. An application of maximum thrust in an attempt to climb out of the cloud quickly led to the complete failure of all four engines. Restart attempts were eventually successful in restoring enough thrust to complete the flight with ATC assistance in respect of altitude and speed. No adverse consequences for the 231 passengers and 14 crew members on board were reported to have arisen as result of the event. However, a series of subsequent examinations of both the aircraft and its engines (the latter both on and off wing) subsequently disclosed extensive damage especially but not only to all the engines (which were replaced) and to the airframe, the avionics and the electrical systems.  

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